1. Technical Field
The invention relates to an arrangement for digital transmission of information via lines between a line termination of a telecommunication network and subscribers connected to the line termination, wherein at least one subscriber terminal is connected to a network termination via an electric line, wherein the network termination is connected to the line termination via a line having metallic conductors and wherein the line termination has a voltage source for supplying power to itself and to the network termination and the subscriber terminals (DE 43 43 456 A1).
2. Description of the Prior Art
Digital transmission techniques can provide services of different types that are useful to subscribers of a telephone network. The services include, e.g., telephone, fax, IDN and ISDN (basic and primary multiplexed connections). The subscriber exchange area of the telephone network, i.e. the subscriber line network, is particularly important. Also of interest are other subscriber connections, for example point-to-point connections. All conventional xe2x80x9cnetwork structuresxe2x80x9d have a network termination with a power supply unit to which the subscriber terminals of at least one subscriber are connected.
A subscriber line network is described, for example, in the publication DE 43 43 456 A1 cited above. The line termination is formed as a cable distribution terminal containing active components and connected to an exchange of the telephone network via optical and/or electrical cables or lines. The network terminations include active components and will be referred to as termination distribution boxes. The termination distribution boxes are connected to the cable distribution terminal via cables and lines, respectively, which contain at least electrical conductors. In this way, the cable distribution terminal can supply power centrally from the voltage source to all active components of the cable distribution terminal and to the termination distribution box and also to the subscriber terminals. The termination distribution boxes and the associated switch units can be installed, for example, in the building of one or several subscribers. Only short electrical wires are routed from there to the subscribers"" equipment. In this way, each subscriber has the option of being connected to channels with a transmission rate of, for example, 2 MBPS. This arrangement has proven to be effective in practice.
It is the object of the invention to further increase the reliability of the aforementioned arrangement for transmitting information.
The object is solved according to the invention in that
two separate power supply units are arranged in the network termination, wherein one of the power supply units powers active components of the network termination and the other unit powers the subscriber terminals, and
the two power supply units are connected to the voltage source of the line termination via separate lines.
With this arrangement, the two separate power supply units of the network termination and the subscriber terminals are each connected independent of each other to the central voltage or current source, respectively, of the line termination. A malfunction on the subscriber side, for example a malfunction due to a short circuit, does then not affect the network termination. The network termination and consequently the transmission system of the network termination remain operational. Modern telecommunication networks include a management system so that the malfunction can be localized and repaired within a short time.
This arrangement is particularly advantageous if two or more subscribers are connected to a network termination. The management system is then not only able to sense, but also to localize a malfunction at one of the subscriber sites. The malfunction can then be quickly repaired.
The invention will be fully understood when reference is made to the following detailed description taken in conjunction with the accompanying drawing.